Chest Radiograph Anomaly Identification with Wasserstein Alignment

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Solution Overview

Problem

Conventional domain adaptation methods for chest radiographs face challenges in correctly positioning features, leading to extraction errors and high parameter quantities, with limited classification precision and generalization ability due to differences in data distribution between training and test sets.

Innovation Solution

A Wasserstein distance and difference metric-combined chest radiograph anomaly identification method using a swin transformer network for multi-scale feature extraction, coupled with Wasserstein distance and contrastive domain discrepancy to select source domain samples closest to the target domain, narrow intra-class distances, and expand inter-class distances, enhancing feature alignment and classification prediction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional domain adaptation methods are used for chest radiograph anomaly identification, then the model can be trained on source domain data, but the model suffers from poor generalization ability and significant performance decrease when applied to target domain data with different distribution

Engineering Contradiction:
Improvegeneralization abilityVSAvoiddomain distribution difference
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameter of domain distribution alignment by introducing Wasserstein distance and contrastive domain discrepancy as loss functions. These mathematical parameters quantify and minimize the distribution difference between source and target domains, enabling the model to adapt to different domain distributions while maintaining reliable anomaly identification performance across domains

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent combines multiple feature extraction components (multi-scale feature extraction, contrastive domain discrepancy module, and Wasserstein distance module) into a composite domain adaptation framework. This composite structure integrates different mechanisms for feature alignment and domain invariant representation, resolving the contradiction between reliability and adaptability through synergistic combination of multiple techniques

Inventive Principle:
Principle #40Composite materials

2Extent of automation

If adversarial training processes are used in deep domain adaptation approaches, then feature extraction and model training are integrated into end-to-end learning, but the feature extractor pays more attention on background regions and results in inability to correctly position anomalies

Engineering Contradiction:
Improveend-to-end learning integrationVSAvoidanomaly positioning accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent applies local quality by introducing a contrastive domain discrepancy module that specifically focuses on anomaly region features rather than treating the entire image uniformly. This module enhances the local feature representation quality in anomaly regions while maintaining the end-to-end learning framework, thereby resolving the contradiction between automation and positioning precision

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces a domain discriminator as an intermediary component that mediates between the feature extractor and the final classification. This intermediary provides gradient reversal learning to enforce domain invariance while the contrastive domain discrepancy module acts as another intermediary to specifically guide anomaly region feature alignment, preventing the feature extractor from focusing excessively on background regions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conditional adversarial mechanism is expanded to improve domain adaptation performance, then feature alignment is improved, but the parameter quantity becomes huge

Engineering Contradiction:
Improvefeature alignment accuracyVSAvoidparameter quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and isolates the essential domain adaptation function into a separate domain discriminator module with gradient reversal learning, rather than embedding complex conditional adversarial mechanisms throughout the entire network. This extraction achieves effective feature alignment while keeping the parameter quantity manageable by concentrating the domain adaptation functionality in a dedicated component

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the domain adaptation task into distinct functional modules: multi-scale feature extraction, contrastive domain discrepancy calculation, and Wasserstein distance-based domain alignment. This segmentation allows each module to have focused and efficient parameter usage, avoiding the parameter bloat that comes with monolithic conditional adversarial mechanisms

Inventive Principle:
Principle #1Segmentation

4Device complexity

If traditional machine learning models are used for domain transfer, then the approach is simpler, but the classification precision and generalization ability are limited compared to deep learning approaches

Engineering Contradiction:
Improvemodel structure simplicityVSAvoidclassification precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs dynamic feature extraction through multi-scale feature extraction and adaptive feature alignment mechanisms. The model dynamically adjusts feature representations based on domain characteristics and anomaly types, enabling high classification precision while maintaining a relatively structured and manageable architecture compared to fully dynamic deep learning approaches

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS12444169B2Wasserstein distance and difference metric-combined chest radiograph anomaly identification domain adaptation method and system
Publication Date: 2025.10.14 HANGZHOU DIANZI UNIV
  • US12444169B2 patent drawing
  • US12444169B2 patent drawing
  • US12444169B2 patent drawing

AI summary

A Wasserstein distance and difference metric-combined chest radiograph anomaly identification domain adaptation method and a corresponding system are provided. The method includes the following steps: step 1, data preparation and data pre-processing for chest radiographs; step 2, multi-scale feature extraction based on a swin transformer network; step 3, loss minimization based on a Wasserstein distance and a contrastive domain discrepancy; and step 4, using the model to perform chest radiograph prediction after verifying the model. The method selects source domain samples closest to target domain samples, narrows a distance of the same class between the target domain samples and the source domain samples in feature space, and expands a distance between different classes. Meanwhile, a classification prediction task for the chest radiographs is performed by using the multi-scale features, improving a receptive field and capturing more information conducive to the classification prediction task.